Probably bad capacitor.

which one/s? I have looked at them and seem to be ok.

Try to heat up some caps to see if the sound improves, and narrow down to the bad cap.
Blowdryer or solder iron.

Ok, did another test.... an AudioCD played ok, so no connector problem.
I think I'll leave it turned on during the night playing a looped XM file. after that I'll try that cap heating trick

well, no luck with both methods. what to do next?

SB16s are very common: I would just get another one. Just my 2C.

Some things to check:

- Is the signal distorted or only low in amplitude?
- Does the problem occur with both PCM and Adlib/OPL sound?
- Are the line-out and speaker-out jacks both faulty?
- Do signals from line-in pass through correctly? (I guess it will since you say CD input works)
- Can you spot any scratches, interrupted traces, burned or loose components?

Are you sure the jack socket or how you call it is clean and makes a good contact to the jackplug.
Maybe the contacts are off and or oxidized by moist and has a resistance for contact.

- signal is ok, just very low volume on right channel.
- using opl, both channels are very low. using pcm, only the right channel is low, left is ok
- both jacks have the same result.
- line-in pass through is working as supposed.
- did a visual inspection even on those small components on the card and I don't see anything bad.
I have used this PC last month without any problem, yesterday I turned it on again and happens this...

jwt27 wrote:

Some things to check: […]
Show full quote

Some things to check:

- Is the signal distorted or only low in amplitude?
- Does the problem occur with both PCM and Adlib/OPL sound?
- Are the line-out and speaker-out jacks both faulty?
- Do signals from line-in pass through correctly? (I guess it will since you say CD input works)
- Can you spot any scratches, interrupted traces, burned or loose components?

Check the mixer, maybe you can fade Left/Right for any Source (wav, Midi, cd) with another Value.

Did the Problem exist in DOS and Win?

Can you try a Live-CD?

Are you sure it's not a software problem then? It really sounds like your mixer settings are simply off.
I don't know off the top of my head how the SB16 drivers work but is there some way you can reset it to default, like in the mixer program or by removing/replacing some INI file?

If it does turn out to be a hardware problem I would suspect the DSP/mixer or DAC chip, or perhaps a resistor/capacitor failed somewhere.

Ok did another test, I took the card to another pc, had to reinstall sb16 utilities.
while using diagnose.exe to setup the card, the problem also appears when there's the 8bit/16bit/synth test.
I even used mixerset.exe to configure the vol/pan but it didn't solve.
Tested inside win98se.... same thing....

Looks like a Problem with the Hardware.

when Audio CD plays ok (i think via cable connection sb16 - cd-rom), the connection from sb16 to the Speakers should be okay.

Just dug around in my sound card pile and found a (broken) AWE64 with the same CT1745A + CT1703 combo. Will see if I can figure out how that works.

Do you have (access to) any electronics tools? Things like a multimeter, soldering iron, oscilloscope?

I do have a soldering iron and a cheap dmm but no oscilloscope. I'm not expert at soldering but I can revive my skill on some dead motherboard or something 🤣

jwt27 wrote:

Just dug around in my sound card pile and found a (broken) AWE64 with the same CT1745A + CT1703 combo. Will see if I can figure out how that works.

Do you have (access to) any electronics tools? Things like a multimeter, soldering iron, oscilloscope?